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(a) Periodic qualification of cylinders. (1) Each specification cylinder that becomes due for periodic requalification, as specified in the following table, must be requalified and marked in conformance with the requirements of this subpart. Requalification records must be maintained in accordance with §180.215. Table 1 follows:

(b) DOT 3A or 3AA cylinders. (1) A cylinder conforming to specification DOT 3A or 3AA with a water capacity of 56.7 kg (125 lb) or less that is removed from any cluster, bank, group, rack, or vehicle each time it is filled, may be requalified every ten years instead of every five years, provided the cylinder conforms to all of the following conditions:

(a) Periodic qualification of cylinders. (1) Each specification cylinder that becomes due for periodic requalification, as specified in the following table, must be requalified and marked in conformance with the requirements of this subpart. Requalification records must be maintained in accordance with §180.215. Table 1 follows:

(b) DOT 3A or 3AA cylinders. (1) A cylinder conforming to specification DOT 3A or 3AA with a water capacity of 56.7 kg (125 lb) or less that is removed from any cluster, bank, group, rack, or vehicle each time it is filled, may be requalified every ten years instead of every five years, provided the cylinder conforms to all of the following conditions:

(i) The cylinder was manufactured after December 31, 1945.

Interesting.. I learned something new. Thanks for posting the link.

Gotta have the right tool for the job!

Where is all the stuff MADE IN THE USA?

"Thats what we do Troy. Incredible, Invisible, Imbelivable things. We are an Unseen, Unknown, Unvincible fraternity of craftsman.."

Beverage grade should NEVER be used with any CO2 refrigeration system!! There is to much moisture in a beverage grade CO2. You should use Coleman Grade or Instrument Grade, the idea grade should be 99.99% pure and free of moisture and non-condisables. With some secondary CO2 systems you can use industrial grade as long as its you run it though a liquid filter/dryer before you put it into you system. Please remember there are three types of CO2 system currently being used all over the world inculding the USA and Canada.

USA and Canada
CO2 Secondary - Over 60 currently installed for low temp operating pressure's of 175 - 250 psig depending on load
CO2 DX Cascade Systems - Over 50 currently installed. this is a cascade system using an HFC on the upper cascade and CO2 in the lower cascade operating pressure - 400 to 500 psig on the high side (+20 condensing) 200 - 250 psig (-20 SST)

Both of these systems are subcritical and use only copper pipe. Just like any refrigeration system we must use a dry system without non-condensables or moisture.

The last type of CO2 is Booster system they are the one's that operate at the highest pressures. They use black pipe or SS on the high side from the rack to the condensor/gas cooler back to the rack. They use L and K copper inside the store, but this type of system is HFC free. Can I get an AMEN!!!

Sounds like C02 as a purging/pressure test tool gets a failing grade.
Maybe I should make the switch.
I just purchased a new micron gauge and 1/2 evacuation manifold with 1/2 hoses!! (in the mail)
Cant wait!

With some secondary CO2 systems you can use industrial grade as long as its you run it though a liquid filter/dryer before you put it into you system.
Both of these systems are subcritical and use only copper pipe. Just like any refrigeration system we must use a dry system without non-condensables or moisture.

That's what they said in the class. Thanks for the refresher.

Knowledge is knowing that a tomato is a fruit. Wisdom is knowing not to put it in a fruit salad.